Telephone system.



0. AQSIMPSON.

TELEPHONE SYSTEM.

APPLIOATION rum) NOV. so, 1908.

Patented July 25, 1911.

Qbmfi. Simlozron Witness'em Inuentor fittofney COLUMBIA PLANOGRAPH C(L,WASHlNCITDN, u. c.

CHARLES A. SIMPSON, OF CHICAGO, ILLINOIS, ASSIGNOR TO KELLOGGSWITCHBOARD AND SUPPLY COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OFILLINOIS.

TELEPHONE SYSTEM.

assure.

To all whom it may concern Be it known that I, CHARLES A. SIMPSON, acitizen of the United States, residing in Chicago, county of Cook, andState of Illinois, have invented certain new and useful Improvements inTelephone Systems, of which the following is a specification.

My invention relates to telephone systems of the central battery typeand has for its object the simplification of the circuits and apparatus.

It has been customary in common battery systems to employ both line andcut-01f relays individual to each telephone line, and by the presentinvention I am enabled to eliminate the cut-off relay and at the sametime to maintain the advantages of the systems provided with both lineand cut-off relays.

My invention is illustrated in the accompanying drawing in which theapparatus is shown in its normal or unactuated condition.

In the drawing, the calling substation 1 is provided with theannunciator 2 and con denser 3 in a permanent bridge between lineconductors 4 and 5, and with the transmitter 6 and receiver 7 in abridge maintained normally open by contacts of the switch hook 8.

At the central office, line conductor is connected through the coil ofline relay 9 with the live pole of battery 10. This conductor is alsoconnected directly with the ring contacts 12 of the answering andmultiple jacks. The line lamp 13 has one terminal connected with lineconductor 5 and the other terminal connected with the normally opencontact 14 of line relay 9. The other line conductor 4 is directlyconnected with the tip contacts 15 of the answering and multiple jacksand with the normally closed contact 16 of line relay 9. The springcontact 17 of line relay 9 is connected through the normally closedseries contacts 18 of the answering and multiple jacks with earth. Theadditional sleeve or test contacts 11 are permanently connected togetherthrough a conductor of the multiple cable. The answering subscribersline illustrated at the right of the sheet is provided with apparatussimilar to that of the calling line, the corresponding apparatus beingdesignated by like figures with the sufiix The cord circuit forconnecting these lines for conversation has tip and sleeve talkingstrands,

Specification of Letters Patent.

Application filed November 30, 1908.

Patented July 25, 1911.

Seria1 No. 465,355.

the tip strand extending from the tip 20 of the answering plug throughconductor 21, condenser 22, conductors 23 and 24 including normally opencontacts of answering sleeve relay 37 and the series contacts of theringing key 25 to the tip contact 26 of the call ing plug, and thesleeve strands extend from the sleeve contact 27 of the answering plugthrough conductor 28, condenser 29, conductor 30 and the series contactsof ring ing key 25 to the sleeve contact 31 of the calling plug. The tipand sleeve answering supervisory relays 33 and 34 are connected in abridge between the cord conductors 21 and 28, the portion of this bridgebetween the coils of said relays being connected to earth. The relay 34is preferably of coinparatively high resistance, it being actuatedduring connection over a local circuit. The relay 33 is of lowresistance, one-hundred ohms being found satisfactory, so that thetransmitter current may be fed to the line through its coil. Relays 33and 34 jointly control the circuit of the supervisory signal 35, relay34 being adapted when actuated to complete the circuit of thesupervisory signal, and relay 33 being adapted when actuated tointerrupt the circuit of said signal. The calling supervisory relays 36and 37 are similarly connected in a bridge between conductors 23 and 30,these relays being sim ilarly arranged to control the circuit ofsupervisory signal 38. The relay 37 has the additional contacts 39, and41, the cont acts 39 and 40 maintaining a normal separation between theportions 23 and 24 of the tip talking strand, and the contacts 40 and 41maintaining a normal connection be-' tween the strand 24 and conductor42, which conductor extends to the normally open auxiliary contact 43 ofthe operators listening key 44. The other auxiliary contact 45 isconnected through the test relay 4G with the live pole of battery 10.This relay 46 controls the normally open contacts 47 and 48 adapted whenclosed to complete the circuit of the battery through the tertiarywinding 49 of the operators induction coil. The listening key 44 isadapted when actuated to place the operators receiver 50, the secondaryof the induction coil and condenser 51 in a bridge between the tip andsleeve strands of the cord circuit.

The operators ringing key 25 is adapted when actuated to connect the tipof the call ing plug with the alternating current generator 53, and toconnect the sleeve of the calling plug through the non-inductiveresistance 54 with the grounded pole of said generator.

The connecting plugs used in this system are provided with long sleeveswhich connect both with the ring and test contacts. A ring of insulationseparates the tip and sleeve contacts so that as the plug is withdrawnfrom the ack the ring contact of the jack will disconnect from thesleeve of the plug before the contacts 18 are closed.

In the operation of my system, the sub scriber in charge of substation 1removes his receiver 7 from the switch hook 8 and thus completes acircuit from the live pole of battery 10 through the coil of line relay9, conductor 5, switch hook 8, receiver 7, transmitter 6, line conductort, contacts 16 and 17 of line relay 9 and series contacts 18 of theanswering and multiple jacks to earth. Current in this path actuatesrelay 9 which is preferably so constructed as to complete the contactslet and 17 before contacts 16 and 17 are interrupted. The actuation ofthis relay completes the circuit of the line lamp 13 from the live poleof bat tery 10 through the coil of line relay 9, line lamp 13, contacts14 and 17 of relay 9 and series contact 18 of the answering and multiplecontacts to earth. The display of signal 13 attracts the attention ofthe operator who inserts the answering plug into the answering jack ofthe calling line and thereby interrupts the circuit through the seriescontacts 18 and also completes a circuit from the live pole of battery10 through the coil of line relay 9, ring contacts 12 and 27 of the jackand plug and the coil of supervisory relay 84: to earth. The current inthis path maintains the actuation of line relay 9 and actuatessupervisory relay 3a. A second circuit is also completed by theinsertion of the plug, this circuit including the coil of relay 9, lineconductor 5, switch hook 8, receiver 7, transmitter 6, line conductor l,tip contacts 15 and 20 of the jack and plug, conductor 21 and the coilof supervisory relay 33 to earth. The actuation of relay 33 prevents thedisplay of the supervisory signal 35 which would otherwise have been displayed by the actuation of supervisory relay 34. The operator nowactuates her listening key 44 and obtains the number of the desiredline. Finding this to be the line of substation 1, the operator touchesthe tip contact 26 of her calling plug to the sleeve contact of one ofthe multiple jacks of said line. If the desired line is busy anothercord circuit will be connected with one of the jacks of said line andthe sleeve contact will therefore be maintained at a potential lowerthan that of battery 10. Current will therefore flow from the live poleof battery seer/1i) 10 through the coil of the test relay 16 which ispreferably of very high resistance, the now closed contacts as and 43 ofthe operators listening key 44, conductor 42, con tacts 11 and 10 ofsupervisory relay 37, tip conductor 24: and the tip contacts of theringing key 25 through the tip of the plug to the sleeve contact of thejack thus tested. The current in this path will actuate the test relayas and close its contacts 47 and 4L8,thus sending an impulse of currentthrough the tertiary winding of the operators induction coil, causing adisturbance in the secondary of the coil which is heard in the operatorsreceiver. Assuming, however, that the desired line is found idle, theoperator inserts her calling plug into the jack of the desired line andactuates her ringing key 25. This connects alternating current from thegenerator 53 through the tip contacts of the ringing key over the tipcontacts 26 and 15 of the plug and jack, line conductor l, annunciator2, condenser 3, line conductor 5, ring contacts 12 and 31 of the jackand plug, sleeve contacts of the ringing key 25 and through thenon-inductive resistance 54: to earth. The current in this path beingalternating in character, passes through the condenser 3 and sounds theannunciator 2 calling the desired subscriber to his telephone.

Upon the release of the ringing key and before the desired subscriberanswers his call, a circuit is completed from the live pole of battery10 through the coil of line relay 9, contacts 12 and 31 of the jack andplug, series contacts of ringin key 25, conductor 30 and the coil ofsupervisory relay 37 to earth. Current in this path actuates relays 37and 9, the actuation of relay 37 completing the circuit of suvervisorysignal 38 which indicates to the operator that the called subscriber hasnot yet answered his call.

When the called subscriber answers his call, a circuit is completed fromthe live pole of battery 10 through the coil of line relay 9, conductor5, switch hook 8, receiver 7, transmitter 6, conductor at, tip contacts15 and 26 of the jack and plug, series contacts of ringing key 25,conductor 24., the now closed contacts 10 and 39 of supervisory relay37, conductor 23 and the coilof supervisory relay 36 to earth. Thecurrent in this path actuates relay 36 which interrupts the circuit ofthe superwisory signal 38, thus effacing said signal to indi cate to theoperator that the called subscriber has answered his call. When theconversation is terminated and the subscribers replace their receiversupon their respective switch hooks the circuits of supervisory relays 36and 33 are interrupted causing the contacts of those relays to resumetheir normal positions, which causes the display of supervisory signals35 and 38. l Vhen the operator observes the display of these signals sheremoves her calling and answering plugs from their connections with thejacks and thus severs the circuits of relays 34 and 37 and of linerelays 9 and 9. When these relays resume their normal positions thesignals at the central office are all ettaced and the apparatus is incondition for another call.

It is to be understood that I have here shown and described my inventionwith re spect to certain details to which I do not wish to be undulylimited, it being possible to make certain modifications of thesedetails without departing from the spirit or scope of my invention.

I claim:

1. In a telephone system, the combination with a telephone line, of asource of current, a relay having its coil normally connected between apole of said source and a limb of said line, and the other limb of saidline being normally connected with-the other pole of said source throughcont-acts of said relay, a line lamp, the actuation of said relay beingadapted to complete a locking circuit through said line lamp and thecoil of said relay, substantially as described.

2. In a telephone system, the combination with a telephone line, of acentral source of current, a relay having its coil permanently connectedbetween a pole of said source and a limb of said line, the other limb ofsaid line being normally connected with the other pole of said sourcethrough contacts of said relay and through series contacts of theanswering and multiple jacks, a line lamp, the actuation of said relaybeing adapted to complete the circuit of said lamp through the contactsof said jacks and the coil of said relay, substantially as described.

3. In a telephone system, the combination with a telephone line, of acentral source of current, a relay permanently connected between a poleof said source and a limb of said telephone line, the other limb of saidline being normally connected through contacts of said relay andcontacts of the answering and multiple jacks with the other pole of saidsource, a line lamp, the circuit of said lamp being adapted to becompleted through the contacts of said jacks and contacts of said relaywhen the relay is actuated, a cord circuit to connect with said jacks,the connection of the cord circuit with said jacks being adapted to openthe contacts of said jacks to ei'lace the line lamp, substantially asdescribed.

at. In atelephone system, the combination with a telephone line, 0]": asource of currentat the central oflice, a line relay permanently inseries with said line, a locking circuit for said relay, a line lamp insaid locking circuit, the removal of the receiver at the substationbeing adapted to initially actuate said line relay and to display saidline lamp, said relay being maintained actuated over its lockingcircuit, and a cord circuit adapt ed when connected with the line toeffect the interruption of said locking circuit, substantially asdescribed. 7

5. In a telephone system, the combination with a telephone line, of acord circuit adapted to be connected therewith for conversation, acentral source of current, a relay for the line permanently connectedwith one pole of said source, and a relay for the cord circuitpermanentlyconnected with the other pole of said source, said cord relayand said source being adapted to be connected in a bridge of the talkingcircuit during conversation, a line lamp for the line adapted to bedisplayed by the actuation of said line relay, means adapted uponactuation of the line relay to remove sub-station control of saidsignal, auxiliary contacts associated with the connecting jack of saidline adapted to be separated by the connection of the cord With theline, a signal asso ciated with the cord circuit, the actuation of saidcord relay being adapted to prevent the display of said signal,substantially as described.

6. In a telephone system, the combination with a telephone line, of ajack for said line having talking contacts permanently connected withthe limbs of said line, a central source of current, a relay permanentlyconnected between a pole of said source and a limb of said line, theother limb of said line being normally connected through contacts ofsaid relay and contacts of said jack, in the order named, with the otherpole of said source, a line lamp connected between the first named limbof said line and a normally open contact of said relay, the actuation ofsaid relay being adapted to complete the circuit of said lamp throughthe contacts of said jack, the contacts of said relay and the coil ofsaid relay, whereby the relay is locked in its actuated condition andthe lamp is displayed, the second limb of the line being disconnectedfrom said source at contacts of said relay when the relay is actuated,the locking circuit of said relay including said line lamp being adaptedto be interrupted by the separation of the contacts of the jack when aconnection is established with the line, substantially as described.

7. In a telephone system, the combination with a telephone line, of asingle relay for said line, a line signal adapted to be displayed by theactuation of said relay, a jack for said line, contacts of said jackadapted when separated to interrupt the circuit of said signal, saidrelay thereafter remaining energized over the telephone line, thetalking contacts of said jack being permanently connected with the limbsof said telephone line and one limb of said line being interrupted atcontacts of said relay during conversation, substantially as described.

8. In a telephone system, the combination with a telephone line, abattery at the central ofiice for furnishing current to the substationapparatus, of a locking line relay for said line energized from saidsource, a signal controlled thereby, a cut-ofi' jack associated with theline and having contacts in the circuit of said signal during itsactuation, a cord circuit, the connecton of the cord circuit with theline being adapted to separate the contacts of said cut-off jack,whereby the signal is effaced, substantially as described.

9. In a telephone system, the combination with a telephone line, ofout-0E jacks for said line, a central source of power, a line relay forthe line, a locking circuit for said relay, a line signal adapted to bedisplayed by the actuation of said line relay, a cord circuit adapted tobe connected with the line for conversation, the limbs of said cordcircuit being directly connected wit-h the limbs of said line,substantially as described.

10. In a telephone system, the combination with a telephone line, ofcut-ofi jacks for said line, a central source of power, a line relay forthe line, a line signal adapted to be displayed by the actuation of saidline relay, the circuit of said signal including the coil of said relay,a cord-circuit adapted to be connected with the line for conversation,the limbs of said cord-circuit being directly connected with the limbsof said line, substantially as described.

11. In a telephone system, the combination with a telephone line, of asingle relay for said line secured to the sleeve side there of, a linesignal adapted to be displayed by the actuation of said relay, a jackfor said line, a locking circuit for said relay controlled throughcontacts of said jack, the said contacts of said jack being adapted,when separated, to interrupt the circuit of said signal, substantiallyas described.

12. In a telephone system, the combination with a telephone line, of asingle relay for said line secured to the sleeve side thereof, a linesignal adapted to be displayed by the actuation of said relay, a jackfor said line, contacts of said jack included in the actuating circuitof said relay, the said contacts of said jack being adapted, whenseparated, to interrupt the circuit of said signal, the talking contactsof said jack being permanently connected with the limbs of saidtelephone line, substantially as described.

13. In a telephone system, the combination with a telephone line, of asingle line relay therefor, a line signal adapted-to be displayed by theactuation of said relay, a jack for said line, contacts of said jackincluded in the actuating circuit of said relay, the said contacts ofsaid jack being adapted, when separated, to interrupt the circuit ofsaid signal, and a local circuit for said relay as long as the plug isinserted in the jack, substantially as described.

14. In a telephone system, the combination with a telephone line, of asingle line relay therefor, a line signal adapted to be displayed by theactuation of said relay, a jack for said line, contacts of said jackincluded in the actuating circuit of said relay, the said contacts ofsaid ack being adapted, when separated, to interrupt the circuit of saidsignal, and a local circuit for said relay having a part coincident withthe talking circuit, substantially as described.

15. In a telephone system, the combination with a telephone line, of asingle line relay therefor, a line signal adapted to be displayed by theactuation of said relay, a jack for said line, contacts of said jackadapted, when separated, to interrupt the circuit of saidsignal, thepath for said line relay during conversation being completed over thetelephone line and the tip strand of said cord-circuit as long as thereceiver is ofi? the hook, and over the sleeve strand of the cordcircuitas long as the plug is in the jack, substantially as described.

16. In a telephone system, the combination with a telephone line, of asingle line relay for said line, a line signal adapted to be displayedby the actuation of said relay, means efiective upon actuation of saidrelay to remove sub-station cont-r01 of said signal, a jack for saidline, contacts of said jack adapted, when separated, to interrupt thecircuit of said signal, a supervisory signal and a pair of relays forcontrolling the operation thereof, said line relay being in series withone of said supervisory relays during conversation, whereby said signalis at that time rendered inert, substantially as described.

1'7. In a telephone system, the combination with a telephone line, of asingle line relay for said line, a line signal adapted to be displayedby the actuation of said relay, a jack for said line, contacts of saidjack adapted, when separated, to interrupt the circuit of said signal, asupervisory signal and a pair of relays for controlling the operationthereof, said line relay being in series with one of said supervisoryrelays as long as the plug is in the jack, whereby said signal is atthat time placed in condition to operate, substantially as described.

18. In a telephone system, the combination with a telephone line, of asingle line relay for said line, a line signal adapted to be displayedby the actuation of said relay, means effective upon actuation of saidrelay to remove sub-station control of said signal, a jack for saidline, contacts of said jack adapted, when separated, to interrupt thecircuit of said signal, a supervisory signal and a pair of relays forcontrolling the operation thereof, said line relay being in series withboth of said supervisory relays, substantially as described.

19. In a telephone system, the combination with a telephone line, of asingle line relay therefor, a cord-circuit for making connection withthe line, a supervisory relay associated with each strand of thecordcircuit, a signal for the line placed in operative condition by theactuation of said line relay, and local jack contacts for rendering saidline signal inert when the cord is connected with the line, the path forcurrent of said line relay during conversation including the telephoneline and the winding of said tip supervisory relay, said line relaybeing independently energized over a local circuit including the windingof the sleeve supervisory relay, substantially as described.

Signed by me at Chicago, county of Cook, and State of Illinois, in thepresence of two witnesses.

CHARLES A. SIMPSON.

Witnesses:

CLIFFORD C. BRADBURY, MARJORIE E. GRIER.

Copies of. this patent may be obtained for five cents each, byaddressing the Commissioner of Patents, Washington, D. C.

